If 2 different gases have the same volumes but different masses, how will their densities compare?

The gas having greater mass will have greater density

Explanation:

According to the equation of density

Density =

We see that mass and density are directly proportional to each other if volume is constant

So the gas having greater mass will have greater density

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant. 

False, as a substance changes from a solid to a liquid and from a liquid to a gas the molecules get farther apart from each other